Blood velocity inversion based on magnetoelectric effect is helpful for the development of daily monitoring of vascular stenosis, but the accuracy of blood velocity inversion and imaging resolution still need to be improved. Therefore, a convolutional neural network (CNN) based inversion imaging method for intravascular blood flow velocity was proposed in this paper. Firstly, unsupervised learning CNN is constructed to extract weight matrix representation information to preprocess voltage data. Then the preprocessing results are input to supervised learning CNN, and the blood flow velocity value is output by nonlinear mapping. Finally, angiographic images are obtained. In this paper, the validity of the proposed method is verified by constructing data set. The results show that the correlation coefficients of blood velocity inversion in vessel location and stenosis test are 0.884 4 and 0.972 1, respectively. The above research shows that the proposed method can effectively reduce the information loss during the inversion process and improve the inversion accuracy and imaging resolution, which is expected to assist clinical diagnosis.
Angiography ; Blood Flow Velocity ; Constriction, Pathologic ; Humans ; Neural Networks, Computer

It has been found that the incidence of cardiovascular disease in patients with lower limb amputation is significantly higher than that in normal individuals, but the relationship between lower limb amputation and the episodes of cardiovascular disease has not been studied from the perspective of hemodynamics. In this paper, numerical simulation was used to study the effects of amputation on aortic hemodynamics by changing peripheral impedance and capacitance. The final results showed that after amputation, the aortic blood pressure increased, the time averaged wall shear stress of the infrarenal abdominal aorta decreased and the oscillatory shear index of the left and right sides was asymmetrically distributed, while the time averaged wall shear stress of the iliac artery decreased and the oscillatory shear index increased. The changes above were more significant with the increase of amputation level, which will result in a higher incidence of atherosclerosis and abdominal aortic aneurysm. These findings preliminarily revealed the influence of lower limb amputation on the occurrence of cardiovascular diseases, and provided theoretical guidance for the design of rehabilitation training and the optimization of cardiovascular diseases treatment.
Amputation ; Aorta, Abdominal/surgery* ; Aortic Aneurysm, Abdominal/surgery* ; Blood Flow Velocity/physiology* ; Hemodynamics/physiology* ; Humans ; Lower Extremity ; Models, Cardiovascular ; Stress, Mechanical

By using Doppler sensor and pressure sensor, the cerebrovascular stroke detector can be used to measure the blood flow velocity and blood pressure of the carotid artery. In this study, a variety of signal conversion and isolation processing techniques are proposed for processing and feature extraction of the output signals from the sensors. Finally, effective signal output waveforms that can be used to evaluate the cerebrovascular hemodynamics index (CVHI) are obtained, and the sound signal outputs that can reflect the change characteristics of blood flow velocity and blood pressure signals are generated, which realizes the application functional requirements of the detector.
Blood Flow Velocity/physiology* ; Cerebrovascular Circulation/physiology* ; Hemodynamics/physiology* ; Humans ; Stroke ; Technology

Echocardiogram is vital for the diagnosis of cardiac disease. The heart has complex hemodynamics requiring an advanced ultrasound imaging mode. Cardiac ultrasound vector flow imaging is capable of measuring the actual magnitude and direction of the blood flow velocity, obtaining the quantitative parameters of hemodynamics, and then providing more information for clinical research and diagnosis. This study mainly reviewed several different vector flow imaging techniques for cardiac flow and presented the implementation difficulties, and proposed a diverging wave based high frame rate cardiac ultrasound vector flow imaging. The study discussed the limitation of current ultrasound technology used in the cardiac flow measurement, analyzed and demonstrated the specific reasons for these implementation difficulties and the potential future development.
Blood Flow Velocity ; Heart/physiology* ; Hemodynamics ; Ultrasonography

The radial artery pulse wave contains a wealth of physiological and pathological information about the human body, and non-invasive studies of the radial artery pulse wave can assess arterial vascular elasticity in different age groups.The piezoelectric pulse wave transducers were used to non-invasively acquire radial artery pulse waves at different contact pressures in young and middle-aged and elderly populations. The radial artery waveforms were decomposed using a triangular blood flow model fitting method to obtain forward and reflected waves and calculate reflection parameters. Finally a correlation analysis and regression analysis of the contact pressure P_sensor with the reflection parameters was carried out. The results showed that the reflection parameters RM, RI and R_d had a strong negative correlation with P_sensor in both types of subjects, and the correlation coefficients and slopes of the regression curves were significantly different between the two types of subjects (P<0.05). Based on the results of this study, excessive contact pressure on the transducer should be avoided when detecting radial artery reflection waves in clinical practice. The results also show that the magnitude of the slope of the regression curve between the reflection parameters and the transducer contact pressure may be a potentially useful indicator for quantifying the elastic properties of the vessel.
Middle Aged ; Aged ; Humans ; Blood Pressure/physiology* ; Arteries ; Blood Flow Velocity/physiology* ; Elasticity ; Pulse Wave Analysis ; Radial Artery/physiology*

Objective: To explore the value of tissue Doppler imaging (TDI) combined with two-dimensional speckle tracking imaging (2D-STI) at rest on evaluating microcirculation dysfunction and left ventricular dysfunction in patients with angina and no obstructive coronary artery disease(ANOCA). Methods: This retrospective study recruited 78 ANOCA patients, who hospitalized in the People's Hospital of Liaoning Province from August 2019 to July 2021. These patients underwent conventional echocardiography examination, including TDI and 2D-STI, to evaluate the left ventricular dysfunction, and adenosine stress echocardiography (SE) to evaluate the coronary flow velocity reserve (CFVR). ANOCA patients were divided into coronary microcirculation dysfunction CMD group (CFVR<2) and control group (CFVR≥2) according to CFVR. Clinical data, routine echocardiographic parameters, TDI parameters including isovolumic contraction time (IVCT), isovolumic relaxation time (IVRT), ejection time (ET), and STI parameters including global longitudinal peak strain (GLS), time to peak (TTP); peak strain dispersion (PSD) were compared between the two groups. Binary logistic regression was used to analyze the risk factors of CMD and the predictive value of each parameter to construct a joint prediction model for the diagnosis of CMD in this patient cohort. Results: The mean age was (55.5±11.2) years, 43 (55%) patients were females in this patient cohort, 38 (49%) patienst were didvided into the CMD group and 40 (51%) into the control group. Age, prevalence of hypertension, diabetes, dyslipidemia, and smokers were significantly higher in the CMD group than in the control group (all P<0.05). Tei index was higher, IVCT and TTP were longer, PSD was higher, ET was shorter, and absolute GLS was lower in the CMD group than in the control group (all P<0.05). The results of logistic regression analysis showed that longer IVCT, higher Tei index, higher time to PSD and lower absolute GLS were the independent risk factors of CMD. The ROC curve revealed that the predicting efficacy on CMD was satisfactiory with the combined predictors: AUC=0.884, sensitivity of 82% and specificity of 80%. Conclusions: TDI combined with 2D-STI is associated with a good diagnostic value on the diagnosis of CMD and left ventricular dysfunction in patients with ANOCA, which provides a feasible non-invasive tool for the diagnosis of CMD and risk stratification of patients with ANOCA.
Adult ; Aged ; Angina Pectoris ; Blood Flow Velocity ; Female ; Humans ; Microcirculation ; Middle Aged ; Retrospective Studies ; Ventricular Dysfunction, Left/diagnostic imaging*

This paper describes how to develop a practical new type of atherosclerosis detection device, which can realize real-time measurement and analysis of human atherosclerosis. According to the mechanism of human atherosclerosis, the design objectives of the system are formulated to determine the construction of the platform. The system calculates the pulse wave velocity by measuring the pulse wave of human fingers and toes, adds four blood pressure measurements to the system design, calculates the ankle-brachial index, and comprehensively measures and analyses the degree of human arteriosclerosis.
Ankle ; Atherosclerosis ; Blood Flow Velocity ; Blood Pressure ; Brachial Artery ; Humans ; Pulse Wave Analysis

The study comprehensively puts forward several detection methods to arteriosclerosis and mainly discusses the method for pulse wave velocity (PWV for short) and ankle brachial index (ABI for short). On the basis of methods mentioned above, a portable system device for arteriosclerosis detection based on non-invasive PWV and limb blood pressure is introduced, and expectations for the subsequent engineering design and development direction are given for reference.
Ankle ; Arteriosclerosis/diagnosis* ; Blood Flow Velocity ; Blood Pressure ; Brachial Artery ; Humans ; Pulse Wave Analysis

Blood Flow Velocity ; Coronary Circulation ; Coronary Vessels/diagnostic imaging* ; Humans ; Microcirculation ; Myocardial Ischemia ; Radioisotopes

Vena cava filter is a filter device designed to prevent pulmonary embolism caused by thrombus detached from lower limbs and pelvis. A new retrievable vena cava filter was designed in this study. To evaluate hemodynamic performance and thrombus capture efficiency after transplanting vena cava filter, numerical simulation of computational fluid dynamics was used to simulate hemodynamics and compare it with the commercialized Denali and Aegisy filters, and in vitro experimental test was performed to compare the thrombus capture effect. In this paper, the two-phase flow model of computational fluid dynamics software was used to analyze the outlet blood flow velocity, inlet-outlet pressure difference, wall shear stress on the wall of the filter, the area ratio of the high and low wall shear stress area and thrombus capture efficiency when the thrombus diameter was 5 mm, 10 mm, 15 mm and thrombus content was 10%, 20%, 30%, respectively. Meanwhile, the thrombus capture effects of the above three filters were also compared and evaluated by in vitro experimental data. The results showed that the Denali filter has minimal interference to blood flow after implantation, but has the worst capture effect on 5 mm small diameter thrombus; the Aegisy filter has the best effect on the trapping of thrombus with different diameters and concentrations, but the low wall shear stress area ratio is the largest; the new filter designed in this study has a good filtering and capture efficiency on small-diameter thrombus, and the area ratio of low wall shear stress which is prone to thrombosis is small. The low wall shear stress area of the Denali and Aegisy filters is relatively large, and the risk of thrombosis is high. Based on the above results, it is expected that the new vena cava filter designed in this paper can provide a reference for the design and clinical selection of new filters.
Blood Flow Velocity ; Hemodynamics ; Humans ; Software ; Thrombosis ; therapy ; Vena Cava Filters ; Vena Cava, Inferior